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<a name="Global-Variables"></a>
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<p>
Next: <a href="Register-Variables.html#Register-Variables" accesskey="n" rel="next">Register Variables</a>, Previous: <a href="Stack-Variables.html#Stack-Variables" accesskey="p" rel="prev">Stack Variables</a>, Up: <a href="Variables.html#Variables" accesskey="u" rel="up">Variables</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Types-Index.html#Symbol-Types-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Global-Variables-1"></a>
<h3 class="section">4.2 Global Variables</h3>

<a name="index-N_005fGSYM"></a>
<a name="index-C_005fGSYM"></a>
<p>A variable whose scope is not specific to just one source file is
represented by the &lsquo;<samp>G</samp>&rsquo; symbol descriptor.  These stabs use the
<code>N_GSYM</code> stab type (C_GSYM for XCOFF).  The type information for
the stab (see <a href="String-Field.html#String-Field">String Field</a>) gives the type of the variable.
</p>
<p>For example, the following source code:
</p>
<div class="example">
<pre class="example">char g_foo = 'c';
</pre></div>

<p>yields the following assembly code:
</p>
<div class="example">
<pre class="example">.stabs &quot;g_foo:G2&quot;,32,0,0,0     # <span class="roman">32 is N_GSYM</span>
     .global _g_foo
     .data
_g_foo:
     .byte 99
</pre></div>

<p>The address of the variable represented by the <code>N_GSYM</code> is not
contained in the <code>N_GSYM</code> stab.  The debugger gets this information
from the external symbol for the global variable.  In the example above,
the <code>.global _g_foo</code> and <code>_g_foo:</code> lines tell the assembler to
produce an external symbol.
</p>
<p>Some compilers, like GCC, output <code>N_GSYM</code> stabs only once, where
the variable is defined.  Other compilers, like SunOS4 /bin/cc, output a
<code>N_GSYM</code> stab for each compilation unit which references the
variable.
</p>



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